1. Field of the Invention
The present invention relates to an image forming apparatus using an electrophotographic image forming method.
An electrophotographic image forming apparatus uses the electrophotographic image forming method to form an image on a recording material. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer such as a light emitting diode (LED) printer and a laser beam printer, a facsimile machine, and a word processor.
2. Description of the Related Art
Hitherto, in an electrophotographic image forming apparatus using an electrophotographic image forming process (hereinafter referred to simply as “image forming apparatus”), there has been known a cartridge system. The cartridge system enables a cartridge to be mounted into and removed from a main body of the image forming apparatus so that components and consumable items used in the image forming apparatus are replaceable. Examples of the components to be replaced as the cartridge include an electrophotographic photosensitive drum (hereinafter referred to simply as “photosensitive drum”) and a developing roller acting on the photosensitive drum. Further, the cartridge may also have a configuration in which a developer (toner) used for image formation is contained in the cartridge so that the developer is supplied to the main body through the replacement of the cartridge.
Those cartridge systems allow users themselves to perform maintenance of the image forming apparatus without service engineers. Thus, those cartridge systems have been widely used in image forming apparatus.
Further, there has also been known a configuration in which the cartridge is mountable into the main body in a state in which the cartridge is supported by a movable support member. For example, Japanese Patent Application Laid-Open No. H10-78737 discloses, in FIG. 1, a configuration in which process units respectively including image bearing members (photosensitive drums) are mounted into the main body of the image forming apparatus while being guided by a guide rail through a slide rail. In the disclosed configuration, four process units are mountable into the main body and each of the process units is mountable into and removable from the main body separately and independently. Each of the process units is moved along an axis of the corresponding image bearing member (photosensitive drum) while being supported by the slide rail and the guide rail to be mounted into the main body.
Further, there has also been known a technology of providing a support member for loading a plurality of the cartridges to the image forming apparatus and pulling out the support member from inside the main body of the image forming apparatus to a predetermined position to enable replacement work to be performed for various types of cartridges. As an example of the technology, Japanese Patent Application Laid-Open No. 2012-145877 discloses a configuration in which the main body of the image forming apparatus includes two support members. Specifically, in the configuration disclosed in Japanese Patent Application Laid-Open No. 2012-145877, the support member for supporting the plurality of photosensitive member units including the photosensitive drums and the support member for supporting the plurality of developing cartridges are provided separately. As a result, the developing cartridges can be more easily replaced. In the configuration disclosed in Japanese Patent Application Laid-Open No. 2012-145877, the plurality of photosensitive member units for respectively forming images in different colors are supported by the same support member. Further, the plurality of developing cartridges for respectively forming images in different colors are supported by the same support member.
There is the following problem in a case where the plurality of cartridges (the plurality of photosensitive member units or the plurality of developing cartridges) for respectively forming the images in different colors are supported by the same support member to be mounted into the main body as in the case of the configuration disclosed in Japanese Patent Application Laid-Open No. 2012-145877.
Specifically, even when a cartridge for forming an image in a specific color is to be replaced, a user needs to move even a cartridge for forming an image in a color different from that of the cartridge, which is required to be replaced, out of the main body. Specifically, the user needs to pull the support member for supporting the plurality of cartridges out of the main body of the image forming apparatus.
In this case, if a weight of the support member that supports the plurality of cartridges increases along with an increase in capacity of the cartridges, there is a risk in that usability (ease of use) is impaired.
Therefore, a configuration, which allows the cartridge for the specific color alone to be pulled out of the main body for replacement, is preferred. In the case of the configuration in which the plurality of process units are separately and independently mounted into the main body as disclosed in Japanese Patent Application Laid-Open No. H10-78737, however, a plurality of the slide guides for supporting the processing units are required to be prepared for each of the processing units. As a result, the configuration of the image forming apparatus becomes complex.
Therefore, a configuration that improves the usability when the user pulls the support member for supporting the cartridge out of the main body of the image forming apparatus while keeping the simple configuration of the image forming apparatus is desired.